The present invention generally relates to industrial handling equipment and more particularly, to a non-dust generating or dust-free industrial robot which is to be used in places where dust present in air must be substantially completely eliminated such as in so-called clean rooms, e.g., in factories for manufacturing semi-conductors, factories for manufacturing appliances related to optical systems, factories for manufacturing precision products, etc.
In semi-conductor manufacturing factories, optical component assembly mills, etc., it has been a recent trend that presence of fine dust particles having particle diameters in the range of 0.5 to 0.1.mu. or less, becomes the main factors which affect quality and yield of the products. Under the circumstances as described above, even the presence of a human being itself becomes a large obstacle to preserving the non-dust generating or dust-free working condition, thus making it necessary to promote elimination of man-power and introduction of industrial robots.
As a dust scattering prevention device for the purpose as described above, there has conventionally been disclosed, for example, in the "ACCESSORIES CATALOG" published by Intelledex Incorporation, Oregon, U.S.A., a clean room package in which, as shown in FIG. 1, an industrial robot 1 including an upper arm ml, a forearm m2 and an operating hand m3 pivotally connected to each other through joint portions 1a and rotatably mounted on a base 1b via a rotary joint 1f, has its joint portions 1a covered with cover members 2 of a bellows type, thereby to prevent dust generated at the joint portions 1a from scattering out of said joint portions.
In the known arrangement as described above, however, there have been such problems that, since the bellows type cover members 2 themselves function as a pump due to expansion and contraction thereof, dust tends to leak out of gaps between the cover members 2 and the joint portions 1a or that the compactness of the robot 1 is undesirably lost due to use of the bulky cover members 2 on said joint portions 1a. Additionally, since the cover members 2 must be removed for repairing or maintenance of the industrial robot 1, troublesome procedures are required for the repairing and maintenance work.
As a method of preventing scattering of dust without employment of the bellows type cover members as referred to above, there may be considered the practice of completely isolating the interior of the robot from the atmosphere or external air, with respect to the construction of the robot, but as a practical matter, it is difficult to achieve complete airtightness at the movable portions such as rotating portions, sliding portions, etc. of the industrial robot, while, due to the fact that the movable portions themselves tend to be dust generating sources, scattering of dust can not be readily prevented.